Development of Computational Methods for B 1-Corrected Hyperpolarized 13 C MRI Human Studies

Background and Motivation: Hyperpolarized (HP) 13C MR spectroscopic imaging (MRSI) enables quantitative monitoring of enzyme-catalyzed metabolism in human subjects. Using HP [1-13C]pyruvate, the rate of conversion of pyruvate to lactate (kPL) via lactate dehydrogenase (LDH) can be computed per voxel in patients with progressing liver metastases. However, 13C surface transmit/receive (T/R) coils do not have a homogeneous B1 excitation profile, resulting in a gradient of decreasing flip angles for voxels increasingly farther away from the coil. In calculating the kPL for each voxel, the nominal flip angle can be corrected based off the coil’s B1 excitation profile. The goal of this project was to develop and test a novel computational framework to improve kPL accuracy using B1+ correction in human studies.